The invention provides a 3D printer warning device and system. The 3D printer warning device comprise a 3D printer body, a position sensing device, an early warning device and a consumable supplementing device, wherein the 3D printer body comprises a printing nozzle and a controller; the position sensing device is connected with the controller and used for acquiring a real-time printing position of the printing nozzle and sending a printing position signal to the controller; the early warning device is connected with the controller and used for detecting consumables in the 3D printer body, andsending an early warning signal to the controller and warning when the consumables are about to be used up; the controller is connected with the consumable supplementing device and used for terminating the printing operation of the printing nozzle according to the printing position signal and the early warning signal and sending material supplementing information to the consumable supplementing device; and the consumable supplementing device is used for supplementing the consumables to the 3D printer body according to the material supplementing information. According to the invention, the 3Dprinter automatically stops printing operation and supplements the consumables under the condition that the consumables are about to be used up, thereby saving manpower and material resources.